I just activated my first smartphone (a LG K4) and am trying to figure out how to get to my fastmail account on the phone. I downloaded the fastmail mobile app and tried to Log in, but it said that I had and incorrect user name or password. I tried several times, but always received the same response. I am sure that the password that I entered was correct as was my user name (my fastmail address).Can anyone help me with step by step procedures?

I agree that the Fastmail Android or iOS application should work fine with your main login address and password. I have the Fastmail iOS app and it works great, but I don't have an Android device and don't know if the Fastmail Android app works well with your LG phone.

If you are sure you are using the same credentials you use to log in using the web, then you need to file a support request so that Fastmail staff can assist you.

Unfortunately not all Android devices can run the FM App, even though the App can be installed on the particular device.

I have a Lenovo Tab3 7" tablet running Android 5.0.1
It installs the FM app but fails at login.
This tablet is less than 12 months old from release (I think).

I raised a ticket with FM Support.
The issue could not be resolved and apparently some Android devices fail to run the app in the same manner as mine.
The solution offered was to use the browser to login - which is what I do.
It's not as nice as using the App though because the screen is presented as per a desktop device.